A beamforming strategy dedicated to post lens ultrasound imaging and ocular biometry using a 20 MHz multi-element probe

Tony Mateo , Yassine Mofid , Jean-Marc Grégoire , Frédéric Ossant

Ocular ultrasound imaging of the posterior segment is of clinical importance to diagnose pathologies such as choroidal vein occlusion, detached retina or macular degeneration, when OCT is ineffective. Currently, there is no beamforming strategy dedicated to ocular imaging in order to overcome ultrasound aberrations mainly generated by the crystalline lens. Actually, lens acts as a defocusing media due to its biconvex geometry where ultrasound celerity is 10% higher than in the surrounding homogeneous media. As a result, classical linear beamforming images suffer from geometrical distortion with a spatial resolution far below the theoretical values in a homogeneous medium and a low SNR especially at high frequencies. A dedicated beamforming method optimizing post lens imaging is therefore proposed through a linear ultrasound scanning using an ultrasound research scanner in house developed called the ECODERM. The probe consists of a 128 elements linear array working at 20 MHz. The performances of the developed beamforming method were compared with those of the conventional beamforming by means of a wire phantom. The comparison quantifies both axial and lateral resolution, image contrast, and the spatial mislocalization induced by lens. A great improvement is obtained for both image quality and biometry.

Mots clés: eye dedicated beamforming; milocalization correction; ocular biometry; 20 MHz multi-element probe

Domaines: Acoustique [physics.class-ph]

Tony Mateo, Yassine Mofid, Jean-Marc Grégoire, Frédéric Ossant. A beamforming strategy dedicated to post lens ultrasound imaging and ocular biometry using a 20 MHz multi-element probe. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811339⟩